<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <script>
    let date = ['星期一', '星期二', '星期三', '星期四', '星期五', '星期六', '星期七']
    //数值长度
    console.log(date.length);
  </script>
</body>

</html>